Interaction of solid bodies with atmospheres of protoplanets

2018 ◽  
Vol 14 (S345) ◽  
pp. 351-352
Author(s):  
Ernst A. Dorfi ◽  
Florian Ragossnig
Keyword(s):  
Kinetic Energy ◽  
Physical Properties ◽  
Planet Formation ◽  
Frictional Heating ◽  
Protoplanetary Disk ◽  
Small Bodies ◽  
Early Stages ◽  
Break Up ◽  
Solid Bodies ◽  
Stellar Source

AbstractDuring the early stages of planet formation accretion of small bodies add mass to the planet and deposit their energy kinetic energy. Caused by frictional heating and/or large stagnation pressures within the dense and extended atmospheres most of the in-falling bodies get destroyed by melting or break-up before they impact on the planet’s surface. The energy is added to the atmospheric layers rather than heating the planet directly. These processes can significantly alter the physical properties of protoplanets before they are exposed with their primordial atmospheres to the early stellar source when the protoplanetary disk becomes evaporated.

From atmospheric to exoplanet formation retrievals

2021 ◽  
Author(s):  
Paul Mollière ◽  
Tamara Molyarova ◽  
Bertram Bitsch ◽  
Christian Eistrup ◽  
Remo Burn ◽  
...  
Keyword(s):  
Planet Formation ◽  
Protoplanetary Disk ◽  
Atmospheric Composition ◽  
Formation History ◽  
Characterization Studies ◽  
First Time

<p>With new and upcoming observing facilities (JWST and the ELTs), the exoplanet community is poised to precisely measure the chemical inventory of exoplanet atmospheres. This will allow, for the first time, to start investigating whether one of the greatest promises of atmospheric characterization studies holds up: inverting the atmospheric composition to infer the planet formation history encoded in it. In my talk, I will show how such measurements allow to run so-called formation retrievals, which constrain a planet’s formation history using its atmospheric abundances in a Bayesian retrieval framework. I will demonstrate how simple and popular models for the composition of the protoplanetary disk and planet formation could lead to interesting insights when applied in formation retrievals. At the same time, I will discuss how such assumptions are too strongly simplified for making the exoplanet atmosphere — formation connection in practice, and what the most pressing theoretical challenges are. Achieving this connection will be a formidable and interdisciplinary challenge, but the exciting exoplanet observations that lie ahead will allow the community to tackle it in earnest.</p>

scholarly journals Kinetic energy spectra for fragments and break-up density in multifragmentation

2005 ◽  
Vol 623 (1-2) ◽  
pp. 43-47 ◽  
Author(s):  
Ad.R. Raduta ◽  
B. Borderie ◽  
E. Bonnet ◽  
N. Le Neindre ◽  
S. Piantelli ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Energy Spectra ◽  
Break Up

Stopping Super-Earths from growing into Jupiters

2020 ◽  
Author(s):  
Mohamad Ali-Dib ◽  
Andrew Cumming ◽  
Doug Lin
Keyword(s):  
Planet Formation ◽  
Thermal State ◽  
Relative Size ◽  
Protoplanetary Disk ◽  
Outer Envelope ◽  
Dominant Type ◽  
Lower Entropy ◽  
Gas Accretion ◽  
The Hill

<p>Super-Earths are by far the most dominant type of exoplanet, yet their formation is<br />still not well understood. In particular, planet formation models predict that many<br />of them should have accreted enough gas to become gas giants. Here we examine the<br />role of the protoplanetary disk in the cooling and contraction of the protoplanetary<br />envelope. In particular, we investigate the effects of 1) the thermal state of the disk as<br />set by the relative size of heating by accretion or irradiation, and whether its energy is<br />transported by radiation or convection, and 2) advection of entropy into the outer envelope by disk flows that penetrate the Hill sphere, as found in 3D global simulations.<br />We find that, at 0.1 AU, the envelope quickly becomes fully radiative, nearly isothermal, and thus cannot cool down, stalling gas accretion. This<br />effect is significantly more pronounced in convective disks, leading to envelope mass or-<br />ders of magnitude lower. Entropy advection at 0.1 AU in either radiative or convective<br />disks could therefore explain why super-Earths failed to undergo runaway accretion.</p> <p>Ali-Dib, Cumming, & Lin (MNRAS 2020)</p>

scholarly journals The Mg/Fe ratio of silicate minerals in the meteoritic materials and in the circumstellar environment: A case study for the chondritic-like composition

2021 ◽  
Vol 30 (1) ◽  
pp. 45-55
Author(s):  
Péter Futó ◽  
József Vanyó ◽  
Irakli Simonia ◽  
János Sztakovics ◽  
Mihály Nagy ◽  
...  
Keyword(s):  
Solar System ◽  
Crystallization Process ◽  
Planet Formation ◽  
Methodological Approach ◽  
Optical Microscope ◽  
Protoplanetary Disk ◽  
Early Solar System ◽  
System A ◽  
Circumstellar Environment

Abstract Kaba meteorite as a reference material (one of a least metamorphosed and most primitive carbonaceous chondrites fell on Earth) was chosen for this study providing an adequate background for study of the protoplanetary disk or even the crystallization processes of the Early Solar System. Its olivine minerals (forsterite and fayalite) and their Mg/Fe ratio can help us to understand more about the planet formation mechanism and whether or not the metallic constitutes of the disk could be precursors for the type of planets in the Solar System. A multiple methodological approach such as a combination of the scanning electron microscope, optical microscope, Raman spectroscopy and electron microprobe of the olivine grains give the Fe/Mg ratio database. The analyses above confirmed that planet formation in the protoplanetary disk is driven by the mineralogical precursors of the crystallization process. On the other hand, four nebulae mentioned in this study provide the astronomical data confirming that the planet formation in the protoplanetary disk is dominated or even driven by the metallic constituents.

scholarly journals Pebble accretion in self-gravitating protostellar discs

2019 ◽  
Vol 485 (4) ◽  
pp. 4465-4473
Author(s):  
D H Forgan
Keyword(s):  
Time Scales ◽  
Planet Formation ◽  
Density Ratio ◽  
Streaming Instability ◽  
Planetary Cores ◽  
Low Mass ◽  
Spiral Structures ◽  
Protostellar Discs ◽  
Core Accretion ◽  
Solid Bodies

Abstract Pebble accretion has become a popular component to core accretion models of planet formation, and is especially relevant to the formation of compact, resonant terrestrial planetary systems. Pebbles initially form in the inner protoplanetary disc, sweeping outwards in a radially expanding front, potentially forming planetesimals and planetary cores via migration and the streaming instability. This pebble front appears at early times, in what is typically assumed to be a low-mass disc. We argue this picture is in conflict with the reality of young circumstellar discs, which are massive and self-gravitating. We apply standard pebble accretion and streaming instability formulae to self-gravitating protostellar disc models. Fragments will open a gap in the pebble disc, but they will likely fail to open a gap in the gas, and continue rapid inward migration. If this does not strongly perturb the pebble disc, our results show that disc fragments will accrete pebbles efficiently. We find that in general the pebble-to-gas-density ratio fails to exceed 0.01, suggesting that the streaming instability will struggle to operate. It may be possible to activate the instability if 10 cm grains are available, and spiral structures can effectively concentrate them in regions of low gravito-turbulence. If this occurs, lunar mass cores might be assembled on time-scales of a few thousand years, but this is likely to be rare, and is far from proven. In any case, this work highlights the need for study of how self-gravitating protostellar discs define the distribution and properties of solid bodies, for future planet formation by core accretion.

scholarly journals Tracing the physical conditions of planet formation with molecular excitation

2019 ◽  
Vol 15 (S350) ◽  
pp. 181-186
Author(s):  
Richard Teague
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Planet Formation ◽  
Physical Structure ◽  
Protoplanetary Disk ◽  
Field Structure ◽  
Magnetic Field Structure ◽  
Physical Conditions ◽  
Molecular Excitation ◽  
The Magnetic Field

AbstractUnderstanding the physical structure of the planet formation environment, the protoplanetary disk, is essential for the interpretation of high resolution observations of the dust and future observations of the magnetic field structure. Observations of multiple transitions of molecular species offers a unique view of the underlying physical structure through excitation analyses. Here we describe a new method to extract high-resolution spectra from low-resolution observations, then provide two case studies of how molecular excitation analyses were used to constrain the physical structure in TW Hya, the closest protoplanetary disk to Earth.

scholarly journals Terrestrial planet formation in low-mass disks: dependence with initial conditions

2014 ◽  
Vol 9 (S310) ◽  
pp. 218-219
Author(s):  
M. P. Ronco ◽  
G. C. de Elía ◽  
O. M. Guilera
Keyword(s):  
Gas Phase ◽  
Analytical Model ◽  
Ad Hoc ◽  
Planet Formation ◽  
Initial Conditions ◽  
Planetary Systems ◽  
Terrestrial Planet ◽  
Initial Distribution ◽  
Protoplanetary Disk ◽  
Low Mass

AbstractIn general, most of the studies of terrestrial-type planet formation typically use ad hoc initial conditions. In this work we improved the initial conditions described in Ronco & de Elía (2014) starting with a semi-analytical model wich simulates the evolution of the protoplanetary disk during the gas phase. The results of the semi-analytical model are then used as initial conditions for the N-body simulations. We show that the planetary systems considered are not sensitive to the particular initial distribution of embryos and planetesimals and thus, the results are globally similar to those found in the previous work.

Planetesimal formation in the solar nebula

1999 ◽  
Vol 173 ◽  
pp. 17-30
Author(s):  
T.V. Ruzmaikina
Keyword(s):  
Interstellar Dust ◽  
Solar Nebula ◽  
Kuiper Belt ◽  
Asteroid Belt ◽  
Dust Grains ◽  
Small Bodies ◽  
Interstellar Dust Grains ◽  
Formation And Evolution ◽  
Cloud Cores ◽  
Solid Bodies

AbstractTerrestrial planets, cores of giant planets and small bodies of the solar system − comets and asteroids − resulted from the coagulation of interstellar dust grains, and grains which were melted or evaporated and condensed again in the solar nebula.The paper describes the growth and processing of dust grains and their aggregates, starting from molecular cloud cores through the formation and evolution of the solar nebula and the accumulation of these aggregates in larger solid bodies − planetesimals. Discussed are the processes which could be responsible for the interruption of accumulation in the region of the asteroid belt, and processes which shaped the Kuiper belt.

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